Javascript Object Literal

- Use object literals as flexible function parameters

Object literals are objects defined using braces ({}) that contain a set of comma separated key value pairs much like a map in Java.

 {key1: "stringValue", key2: 2, key3: ['blue','green','yellow']}

The example above shows an object literal which contains a string, number, and array of strings. As you may imagine object literals are very handy in that they can be used as generic for passing in arguments to a function. The function signature does not change if you choose to require more properties in a function. Consider using object literal as the parameters for methods.

 function doSearch(serviceURL, srcElement, targetDiv) {
     var params = {service: serviceURL, method: "get", type: "text/xml"};
     makeAJAXCall(params);
 }

 function makeAJAXCall(params) {
     var serviceURL = params.service;
 ...
} 

Also note that with object literals you can pass anonymous functions as may be seen in the following example:

 function doSearch() {
    makeAJAXCall({serviceURL: "foo",
        method: "get", 
        type: "text/xml",
        callback: function(){alert('call done');}
    });
 }
 
 function makeAJAXCall(params) {
     var req = // getAJAX request;
     req.open(params.serviceURL, params.method, true);
     req.onreadystatechange = params.callback;
     ...
 }

Object literals should not be confused with JSON which has similar syntax. JSON is a subset of object literal notation of javascript.

 self.dashboards = {
     "/admin/license/installLicense.action" : "system:administration_setupsupport.3",
     "/admin/agent/listAgents.action" : "system:administration_agents.5"
    }

*** when needed, say there is '/' or space character, we can use double quote to escape it.